Method and apparatus for reforming can bottom to provide improved strength

Abstract

A method and apparatus for reforming a bottom of a drawn and ironed beverage container is disclosed. The container has a longitudinal axis and a side wall parallel with the longitudinal axis. The bottom has an outer annular wall, a convex U-shaped portion and a preformed bottom wall. The preformed bottom wall includes a center domed portion. The bottom further has an annular, substantially longitudinal wall joining the domed portion and the convex U-shaped portion. The apparatus comprises a roller movable from an inward position where the roller does not contact the annular, substantially longitudinal wall to an outward position where the roller contacts the annular, substantially longitudinal wall, and a movable actuator to move the roller into engagement with and circumferentially about the annular, substantially longitudinal wall to reform the substantially longitudinal wall. The movable actuator moves the roller into engagement with the annular, substantially longitudinal wall to reform the substantially longitudinal wall to achieve a negative angle (A) relative to the longitudinal axis of the container.

We claim: 
     
       1. An apparatus for reforming a bottom of a drawn and ironed beverage container, said container having a longitudinal axis; a side wall parallel with said longitudinal axis; the bottom having an outer annular wall, a convex U-shaped portion, a preformed bottom wall, including a center domed portion; and an annular, substantially longitudinal wall joining said domed portion and said convex U-shaped portion; said apparatus comprising: a roller movable from an inward position where said roller does not contact said annular, substantially longitudinal wall to an outward position where said roller contacts said annular, substantially longitudinal wall; and   a movable actuator to move said roller into engagement with and circumferentially about said annular, substantially longitudinal wall to reform said substantially longitudinal wall.   
     
     
       2. The apparatus of claim 1 wherein said movable actuator moves said roller into engagement with said annular, substantially longitudinal wall to reform said substantially longitudinal wall to achieve a negative angle (A) relative to said longitudinal axis of said container. 
     
     
       3. The apparatus of claim 1, wherein said apparatus includes a plurality of rollers, each of said rollers movable from a radially inward position where said rollers do not contact said annular, substantially longitudinal wall to a radially outward position where said rollers contact said annular, substantially longitudinal wall. 
     
     
       4. The apparatus of claim 1 including a container support for inwardly supporting said container. 
     
     
       5. The apparatus of claim 4 wherein said container support supports said container along a lower end of said container. 
     
     
       6. The apparatus of claim 4 wherein said container support comprises a jig, said jig supporting said container along a lower end of said container. 
     
     
       7. The apparatus of claim 4, wherein said container support comprises a jig, said jig supporting said container along a bottom peripheral profile portion substantially corresponding in shape to said outer annular wall of said container, said bottom peripheral profile portion of said jig being mated with said outer annular wall of said container. 
     
     
       8. The apparatus of claim 4 wherein said movable actuator moves said roller into engagement with said annular, substantially longitudinal wall in opposition to said container support. 
     
     
       9. The apparatus of claim 1, wherein the perimeter of said roller has a downwardly tapered portion which, when placed against said substantially longitudinal wall, reforms said substantially longitudinal wall to achieve a negative angle (A) relative to the longitudinal axis of said container. 
     
     
       10. The apparatus of claim 1 wherein said apparatus includes three rollers. 
     
     
       11. A method of reforming a bottom of a drawn and ironed beverage container, said container having a longitudinal axis; a generally cylindrical side wall parallel with said longitudinal axis; the bottom having an outer annular wall, a convex U-shaped portion, a preformed bottom wall including a center domed portion, and an annular, substantially longitudinal wall joining said domed portion and said convex U-shaped portion, said method comprising: providing said drawn and ironed beverage container;   providing a reforming roller; and   moving said reforming roller radially into engagement with said substantially longitudinal wall of said beverage container, said reforming roller rotating along said longitudinal wall and circumferentially about an arcuate path, wherein said reforming roller affects the angle of said substantially longitudinal wall.   
     
     
       12. The method of claim 11 including the step of providing radial inward support for said container. 
     
     
       13. The method of claim 12, wherein said reforming roller is rotated about an arcuate path equidistant from an axis that is coaxial with the longitudinal axis of the container. 
     
     
       14. The method of claim 12 wherein said providing radial inward support includes supporting said container along a lower end of said container. 
     
     
       15. The method of claim 12 wherein said providing radial inward support includes supporting said container in a jig, said jig supporting said container along a lower end of said container. 
     
     
       16. The method of claim 12 wherein said providing radial inward support includes supporting said container in a jig, said jig supporting a bottom peripheral profile portion substantially corresponding in shape to said outer annular wall of said container, and mating the bottom peripheral profile portion of said jig with said outer annular wall. 
     
     
       17. The method of claim 11, wherein said reforming roller affects the angle of said substantially longitudinal wall by achieving a negative angle (A) from the longitudinal axis of said container. 
     
     
       18. The method of claim 11, wherein said roller has a tapered peripheral portion which, upon engagement with said substantially longitudinal wall, reforms said substantially longitudinal wall to achieve a negative angle from the longitudinal axis of said container. 
     
     
       19. An apparatus for reforming a bottom of a drawn and ironed beverage container, said container having a longitudinal axis; a side wall parallel with said longitudinal axis; the bottom having an outer annular wall, a convex U-shaped portion, a preformed bottom wall, including a center domed portion; and an annular, substantially longitudinal wall joining said domed portion and said convex U-shaped portion; said apparatus comprising: means for radially inwardly supporting a lower end of said container;   a roller movable from a radially inward position where said roller does not contact said annular, substantially longitudinal wall to a radially outward position where said roller contacts said annular, substantially longitudinal wall; and   a movable actuator to move said roller in opposition to said radial inward supporting means and into engagement with and circumferentially about said annular, substantially longitudinal wall to reform said substantially longitudinal wall.   
     
     
       20. The apparatus of claim 19 wherein said movable actuator moves said roller into engagement with said annular, substantially longitudinal wall to reform said substantially longitudinal wall to achieve a negative angle (A) relative to said longitudinal axis of said container. 
     
     
       21. A method for reforming a bottom of a drawn and ironed beverage container, said container having a longitudinal axis; a side wall parallel with said longitudinal axis; the bottom having an outer annular wall, a convex U-shaped portion, a preformed bottom wall, including a center domed portion; and an annular, substantially longitudinal wall joining said domed portion and said convex U-shaped portion; said method comprising: providing said drawn and ironed beverage container;   radially inwardly supporting a lower end of said container;   providing a roller;   moving said roller from a radially inward position where said roller does not contact said annular, substantially longitudinal wall to a radially outward position where said roller contacts said annular, substantially longitudinal wall; and   circumferentially moving said roller in opposition to said radial inward supporting means and in engagement with said annular, substantially longitudinal wall to reform said substantially longitudinal wall.   
     
     
       22. The method of claim 21 wherein said movable actuator moves said roller into engagement with said annular, substantially longitudinal wall to reform said substantially longitudinal wall to achieve a negative angle (A) relative to said longitudinal axis of said container.